Surgical tools for use in the dissection of bone during surgical procedures are conventional in the art. Many such tools employ pneumatic motors to rotate the cutting element of a resecting tool. In their most basic form, such surgical instruments comprise a motor portion having a rotary shaft, a resecting tool having a cutting element, and a chuck for connecting the resecting tool to an outer end of spindle of the rotary shaft. These surgical instruments have been created from carbon steel because of the need for high material hardness and ability to withstand the wear of operating at high speeds. Also, thin hardened cases, such as titanium nitride and titanium aluminum nitride have been applied to the bore of the motor housing to reduce wear caused by the rotating vanes. In addition to steel, resecting tools in some instances have been formed to tungsten carbide.
A fairly recent diagnostic technique involves the use of magnetic resonance imaging (MRI) machines or other machines which create or utilize very high strength magnetic fields. These machines provide an image of internal organs of the human body. Surgeons may utilize the images from such machines to guide them in performing subsequent surgery. It would be advantageous to be able to perform surgery using pneumatic resecting tools while in the MRI suite. However, the resident high magnetic field will attract magnetic objects, potentially creating unguided missiles. Because of the ferrous metal in the motors, these pneumatic resecting tools are not used.
For use during MRI operations, it would be very desirable to create surgical tools using nonferrous materials that would be unaffected by magnetic fields. However, nonferrous metals such as titanium have traditionally only been used in implants and hand tools such as pliers and nippers, not in pneumatic resecting motors, which rotate at high speeds.